Can an algorithm predict appropriate utilization of emergency venous studies?

Abstract Venous duplex evaluation (VDE) has virtually supplanted venography in the diagnosis of deep vein thrombosis (DVT). To control low yield of VDE of ambulatory patients, performed at “off-hours,” we adopted an algorithm to improve the selection process and to increase efficiency. “Off-hours” studies are those performed after the normal daily working hours, weekends, or holidays. From January 1, 1996, through December 31, 1998, we performed 5393 lower extremities VDE, utilizing color duplex imaging with video taping. 2535 studies were done during the eighteen months prior to adoption of the algorithm on July 1, 1997 and 2858 studies were performed during the subsequent eighteen months. During the first 18 months, 314 requests for emergency studies came from the Emergency Department (ED). 132 were “off-hours” and 24 (18.2%) were positive for DVT compared to 427 after adoption of the algorithm, of which 79 were “off-hours” with 24 being positive for DVT (30.3%). Using an algorithm for dealing with requests for VDE originating in the ED on outpatients at “off-hours” resulted in an overall decrease in requests as well as a greater yield of positive studies without apparent compromise of the quality of care.